Numerous punch configurations for sheet metal are known in the art; e.g. the Philip U.S. Pat. No. 1,097,669 issued May 26, 1914, the Abery U.S. Pat. No. 891,516 issued June 23, 1908; the Duncan U.S. Pat. No. 2,287,168 issued June 23, 1942 and the Ehrens et al U.S. Pat. No. 3,580,269 issued May 25, 1971, illustrate punch constructions of various types.
In many punching applications, a small diameter pilot hole is first punched in the workpiece so that a draw stud of a larger diameter punch and die set can be inserted therethrough to punch a desired larger diameter hole. There is a need to improve pilot hole punches to increase the range of thicknesses of material punchable by a given pilot hole punch by lowering the force required to force the punch through the material.